on 10/1/02 9:52 AM, David J Binnington at david@DJBELECT.KEME.CO.UK wrote:

Hi David,

I am a newbie to the PIC (and Microcontrollers in general) but I (think) I
can answer all of the questions correctly. However I could honestly not do
the task you are employing the guy to do, and as an employer, I would not
see any value in the following type of questionaire.

> Question 1:

> A 16F877 is to be used with a 20MHz crystal.  Which of the following CONFIG
> words would be the most appropriate?
>
> a)      __FUSES _CP_OFF&_WDT_ON&_RC_OSC&_PWRTE_ON&_LVP_OFF&_BODEN_ON&_MCLRE_ON
> b)      __FUSES _CP_OFF&_WDT_ON&_XT_OSC&_PWRTE_ON&_LVP_OFF&_BODEN_ON&_MCLRE_ON
> c)      __FUSES _CP_OFF&_WDT_ON&_HS_OSC&_PWRTE_ON&_LVP_OFF&_BODEN_ON&_MCLRE_ON
> d)      Do not know

Answer: c) - but wouldn't you want the Code Protect on? :-)

> Question 2:
>
> The following code extract from a 16F628 program does not work as intended.
>
> ;PORTB Setup
> ;-----
> clrf    STATUS,RP0                      ;Set BANK 0
> movlw   B'11111111'
> movwf   PORTB                           ;Set PORTB output latches to all 1's
>
> bsf     STATUS,RP0                      ;Set BANK 1
>
> movwf   TRISB                           ;Set PORT B to all outputs
>
> clrf    STATUS,RP0                      ;Set BANK 0
>
>
> What would be the result?
>
> a) Sets all I/O pins of PORT B to output 1
> b) Sets all I/O pins of PORT B to output 0
> c) Sets all I/O pins of PORT B to input or tristate
> c) The state of PORTB cannot be determined

Answer: c) - You missed loading the W register before the movf to TRISB

> Question 3:
>
> A 16F877 has a 10MHz crystal.  What is the execution time for a single cycle
> instruction?
>
> a) 100nS
> b) 4uS
> c) 250nS
> d) 400nS
> e) None of the above

Answer: d)

How did I do? Throw some tough ones at them! :-)

Regards,

Sean Alcorn

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